The kinetics and mechanism of protein folding is being studied using a variety of laser techniques. These include measuring the rate of a specific intramolecular contact from quenching of tryptophan fluorescence by cysteine, measurements of equilibria and kinetics of an ultra-fast folding protein (villin subdomain) using laser temperature jump, and single molecule fluorescence measurements of a two-state folder (cold shock protein) to obtain dynamical information for determination of entropy barriers to folding. The results are being used to develop analytical statistical mechanical models of protein folding and to test the results of molecular dynamics simulations.